The inset-block-startCSS property defines the logical block start offset of an element, which maps to a physical inset depending on the element's writing mode, directionality, and text orientation. It corresponds to the top, right, bottom, or left property depending on the values defined for writing-mode, direction, and text-orientation.

Disabled From version 69: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled). To change preferences in Chrome, visit chrome://flags.

EdgeNo support
No

FirefoxFull support
63

Full support
63

No support41 — 63

Alternate Name

Alternate Name Uses the non-standard name: offset-block-start

No support38 — 51

Disabled

Disabled From version 38 until version 51 (exclusive): this feature is behind the layout.css.vertical-text.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

IENo support
No

OperaFull support
56

Disabled

Full support
56

Disabled

Disabled From version 56: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).

SafariNo support
No

WebView AndroidNo support
No

Chrome AndroidNo support
No

Edge MobileNo support
No

Firefox AndroidFull support
63

Full support
63

No support41 — 63

Alternate Name

Alternate Name Uses the non-standard name: offset-block-start

No support38 — 51

Disabled

Disabled From version 38 until version 51 (exclusive): this feature is behind the layout.css.vertical-text.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

Opera AndroidFull support
48

Disabled

Full support
48

Disabled

Disabled From version 48: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).